datastreams: safer and faster schema serialization (#6042)

The original implementation contained unused code and used
replace calls after serializing an object to JSON. The strings
could have contained parts that the replace call would have
matched (while unlikely due to the content). This now directly
serializes to JSON and does not have that issue anymore. That
should also be faster overall.

Author: BridgeAR

packages/dd-trace/src/datastreams/schemas/schema_builder.js

@@ -15,13 +15,13 @@ class SchemaBuilder {
     this.properties = 0
   }
 
+  // TODO: This is only used in tests. Let's refactor the code and stop exposing the cache.
   static getCache () {
     return CACHE
   }
 
   static getSchemaDefinition (schema) {
-    const noNones = convertToJsonCompatible(schema)
-    const definition = jsonStringify(noNones)
+    const definition = toJSON(schema)
     const id = fnv64(Buffer.from(definition, 'utf8')).toString()
     return new Schema(definition, id)
   }
@@ -96,42 +96,43 @@ class OpenApiComponents {
   }
 }
 
-function convertToJsonCompatible (obj) {
-  if (Array.isArray(obj)) {
-    return obj.filter(item => item !== null).map(item => convertToJsonCompatible(item))
-  } else if (obj && typeof obj === 'object') {
-    const jsonObj = {}
-    for (const [key, value] of Object.entries(obj)) {
-      if (value !== null) {
-        jsonObj[key] = convertToJsonCompatible(value)
+// This adds a single whitespace between entries without adding newlines.
+// This differs from JSON.stringify and is used to align with the output
+// in other platforms.
+function toJSON (value) {
+  // eslint-disable-next-line eslint-rules/eslint-safe-typeof-object
+  if (typeof value === 'object') {
+    if (value === null) {
+      return 'null'
+    }
+    if (Array.isArray(value)) {
+      let result = '['
+      for (let i = 0; i < value.length; i++) {
+        if (i > 0) {
+          result += ', '
+        }
+        result += value[i] == null ? 'null' : toJSON(value[i])
       }
+      return `${result}]`
     }
-    return jsonObj
-  }
-  return obj
-}
-
-function convertKey (key) {
-  if (key === 'enumValues') {
-    return 'enum'
+    let result = '{'
+    for (const [key, objectValue] of Object.entries(value)) {
+      if (objectValue != null && typeof key === 'string') {
+        const converted = toJSON(objectValue)
+        if (converted !== undefined) {
+          if (result !== '{') {
+            result += ', '
+          }
+          result += `"${key}": ${converted}`
+        }
+      }
+    }
+    return `${result}}`
   }
-  return key
-}
-
-function jsonStringify (obj, indent = 2) {
-  // made to stringify json exactly similar to python / java in order for hashing to be the same
-  const jsonString = JSON.stringify(obj, (_, value) => value, indent)
-  return jsonString.replaceAll(/^ +/gm, ' ') // Replace leading spaces with single space
-    .replaceAll('\n', '') // Remove newlines
-    .replaceAll('{ ', '{') // Remove space after '{'
-    .replaceAll(' }', '}') // Remove space before '}'
-    .replaceAll('[ ', '[') // Remove space after '['
-    .replaceAll(' ]', ']') // Remove space before ']'
+  return JSON.stringify(value)
 }
 
 module.exports = {
   SchemaBuilder,
   OpenApiSchema,
-  convertToJsonCompatible,
-  convertKey
 }